System and method for bypassing an access point in a local area network for P2P data transfers

ABSTRACT

A system and method for bypassing an access point in a wireless Local Area Network (LAN) for direct point-to-point data transfers are provided. A user device in the wireless LAN is equipped with a primary local wireless interface establishing a wireless communication link with an access point of the wireless LAN, a secondary local wireless interface used for direct point-to-point (P2P) file transfers, and a P2P file transfer application. When the P2P application desires to transfer a data file to another user device within the wireless LAN, the user device determines whether the other user device is within a coverage area of the secondary local wireless interface and whether the file transfer meets one or more alternate transfer criterion. If so, the data file is transferred to the other user device via a direct P2P wireless communication link, thereby bypassing the access point of the wireless LAN.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 11/443,761, filed on May 31, 2006, the disclosure of which ishereby incorporated by reference in its entirety

FIELD OF THE INVENTION

The present invention relates to a system for bypassing an access pointin a local wireless network for direct point-to-point (P2P) datatransfers.

BACKGROUND OF THE INVENTION

The in-home Local Area Network (LAN) traffic model is beginning tochange due to Digital Rights Management (DRM) and the storage of largemultimedia collections on various devices coupled to the in-home LAN.For example, a consumer may have multiple Personal Video Recorders(PVRs), such as the TiVo Series 2 PVR, connected to the consumer'sin-home LAN, wherein multimedia content may be transferred from one PVRto another via the in-home LAN. The most common in-home LANs arewireless LANs formed using local wireless access points, such as IEEE802.11 access points. The resulting problem is that transferringmultimedia files between devices, such as PVRs, using a traditionalwireless LAN results in very inefficient use of the limited unlicensedradio frequency (RF) spectrum. More specifically, if, for example, theIEEE 802.11g communication standard is used, each transfer of amultimedia file uses a first portion of the IEEE 802.11g RF spectrum fora first wireless communication link between a source device and theaccess point and a second portion of the IEEE 802.11g RF spectrum for asecond wireless communication link between the access point and adestination device. Further, contention for bandwidth at the accesspoint as packets are switched from receive to transmit adds additionaldelay, thereby further wasting the RF spectrum and compute cycles on thePVRs and access point. Overall, this transfer process can be slow andburdensome to the application performing the file transfer. In addition,the Quality-of-Service (QOS) for other wireless connections andapplications currently using the access point is also impaired.

Thus, there is a need for a system and method for efficientlytransferring data files between devices in a wireless LAN.

SUMMARY OF THE INVENTION

The present invention provides a system and method for bypassing anaccess point in a wireless Local Area Network (LAN) for directpoint-to-point data transfers. In one embodiment, a user device in thewireless LAN is equipped with a primary local wireless interfaceestablishing a wireless communication link with an access point of thewireless LAN, a secondary local wireless interface for establishingsecondary wireless communication links with other user devices fordirect point-to-point (P2P) file transfers, and a P2P file transferapplication. When the P2P application desires to transfer a data file,such as a media file, from the user device to another user device withinthe wireless LAN, the user device determines whether the other userdevice is within a coverage area of the secondary local wirelessinterface and whether the file transfer meets one or more alternatetransfer criteria. If so, a direct P2P wireless communication link isestablished with the other user device using the secondary localwireless interface, and the data file is transferred to the other userdevice via the direct P2P wireless communication link. As a result, theaccess point for the wireless LAN is bypassed, and as such, the use ofradio frequency spectrum is minimized. If the other user device is notwithin the local wireless coverage area of the secondary local wirelessinterface or if the file transfer does not meet the alternate transfercriteria, then the data file is transferred to the other user device viathe access point.

Those skilled in the art will appreciate the scope of the presentinvention and realize additional aspects thereof after reading thefollowing detailed description of the preferred embodiments inassociation with the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The accompanying drawing figures incorporated in and forming a part ofthis specification illustrate several aspects of the invention, andtogether with the description serve to explain the principles of theinvention.

FIG. 1 illustrates a system 10 for bypassing an access point of awireless Local Area Network (LAN) for direct point-to-point (P2P) datatransfers according to one embodiment of the present invention;

FIG. 2 illustrates an exemplary cross-layer implementation of a protocolstack of a user device enabling bypassing of the access point for directP2P data transfers according to one embodiment of the present invention;

FIG. 3 is a flow chart illustrating an exemplary process for determiningwhether to transfer a data file via the access point or a direct P2Pcommunication link according to one embodiment of the present invention;and

FIG. 4 is a block diagram of a user device operating according to oneembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments set forth below represent the necessary information toenable those skilled in the art to practice the invention and illustratethe best mode of practicing the invention. Upon reading the followingdescription in light of the accompanying drawing figures, those skilledin the art will understand the concepts of the invention and willrecognize applications of these concepts not particularly addressedherein. It should be understood that these concepts and applicationsfall within the scope of the disclosure and the accompanying claims.

FIG. 1 illustrates a system 10 for bypassing an access point 12 of awireless Local Area Network (LAN) 14 for direct point-to-point (P2P)data transfers according to one embodiment of the present invention. Ingeneral, the system 10 includes the access point 12 coupling thewireless LAN 14 to a Wide Area Network (WAN) 16, which is preferably adistributed public access network, such as the Internet. Note that theaccess point 12 may be communicatively coupled to the WAN 16 by a modem(not shown) or the like. The wireless LAN 14 includes the access point12 and user devices 18-22.

The user devices 18-22 may be, for example, Personal Video Recorders(PVRs), media servers, media players for playing media content providedby a media server, desktop computers, notebook computers, PersonalDigital Assistants (PDAs), mobile telephones, or the like, or anycombination thereof. Further, as discussed below with respect to FIGS. 3and 4, each of the user devices 18-22 includes a primary local wirelessinterface establishing a primary wireless communication link with theaccess point 12 and a secondary local wireless interface forestablishing a direct P2P communication link with another user devicefor direct file transfers according to the present invention.

The primary and secondary local wireless interfaces may be implementedusing separate wireless network interface cards, such as, but notlimited to, two IEEE 802.11 network interface cards or a single networkinterface card having multiple radios such as, for example, Netgear'sDouble 108 Mbps Wireless PC Card. The primary local wireless interfacemay be a network interface card operating according to the 802.11gstandard, and the secondary local wireless interface may be a networkinterface card operating according to the 802.11a standard. Since the802.11g standard uses the 2.4 GHz frequency band and the 802.11astandard uses the 5 GHz frequency band, direct P2P file transfers viathe secondary local wireless interface do not affect the availability ofthe primary network associated with the primary local wireless interfacecard. Alternatively, the primary and secondary interfaces may operate innon-overlapping channels of the same frequency band. It should be notedthat the present invention is not limited to the IEEE 802.11 suite ofstandards. The primary and secondary local wireless interfaces mayoperate according to one of the suite of IEEE 802.11 standards, theBluetooth standard, or the like, or any combination thereof.

The user device 18 includes a P2P application 24, which may beimplemented in software. The P2P application 24 operates to transferdata files from the user device 18 to another user device 20, 22 withinthe wireless LAN 14. According to the present invention, the filetransfer may be performed via the access point 12 or a direct P2Pwireless communication link, as described below in detail. In oneembodiment, the data files transferred are multimedia files such as, butnot limited to, movies and television programs. However, the data filesmay alternatively or additionally be any type of data file such asimages, documents, presentations, spreadsheets, and the like. Likewise,the user devices 20 and 22 include P2P applications 26 and 28,respectively.

In one embodiment, the user devices 18-22 are PVRs, such as TiVo PVRs,and the P2P applications 24-28 operate to transfer recorded multimediacontent among the PVRs within the wireless LAN 14. In anotherembodiment, the user devices 18-22 may be a combination of PVRs and, forexample, personal computers, wherein multimedia content such as, but notlimited to, videos, images, and the like is exchanged between the PVRsand personal computers. For example, the user devices 18 and 20 may bePVRs and the user device 22 may be a personal computer. In anotherexemplary embodiment, the user device 18 may be a multimedia server andthe user devices 20 and 22 may be any type of device enabled to playmultimedia provided by the multimedia server such as those manufacturedand sold by Buffalo Techonolgies (http://buffalotech.com).

FIG. 2 illustrates an exemplary cross-layer implementation of a protocolstack of the user device 18 enabling the transfer of data files from theuser device 18 to another user device 20, 22 by either the access point12 or a direct P2P communication link according to one embodiment of thepresent invention. Note that this discussion is equally applicable tothe user devices 20 and 22. As illustrated, the protocol stack includesa P2P application layer 30, which corresponds to the P2P application 24;a file transfer application layer 32, which in this example is a FileTransfer Protocol (FTP) application; and a protocol stack switch 34,which may be implemented in software, hardware, or a combination ofsoftware and hardware. For a primary local wireless interface 36, theprotocol stack further includes a transport layer 38, which in thisexample includes a Transfer Control Protocol (TCP) service and a UserDatagram Protocol (UDP) service; a network layer 40, which in thisexample provides an Internet Protocol (IP) service; a data link layer42, which in this example provides a Media Access Control (MAC) service;and a physical layer 44, which in this example includes an 802.11g (2.4GHz) physical wireless interface. Likewise, for a secondary localwireless interface 46, the protocol stack further includes a transportlayer 48, a network layer 50, a data link layer 52, and a physical layer54, which in this example includes an 802.11a (5 GHz) physicalinterface. Note that the primary and secondary local wireless interfaces36 and 46 may be implemented as separate interfaces, such as separatenetwork interface cards (NICs); or as a single system, such as a singleNIC, wherein the primary and secondary local wireless interfaces 36 and46 share common hardware and software functionality.

It should be noted that while only one secondary local wirelessinterface 46 is illustrated, the present invention is not limitedthereto. The user devices 18-22 may include multiple secondary localwireless interfaces. For example, the user devices 18-22 may includethree secondary local wireless interfaces. The secondary local wirelessinterfaces may be used in combination to provide a high bandwidth directP2P communication channel with another user device or used separately toprovide separate direct P2P communication links with multiple userdevices. Multiple secondary wireless interfaces may also be used toprovide a Multiple Input Multiple Output (MIMO) system such as that inthe proposed IEEE 802.11n standard.

A cross-layer agent 56 and network agents 58 and 60 effectively createan interface between the P2P application layer 30, the file transferapplication layer 32, or both the P2P application layer 30 and the filetransfer application layer 32 and the lower protocol layers 38-44 and48-54. In addition, the cross-layer agent 56 controls the protocol stackswitch 34 to effect file transfers via either the primary local wirelessinterface 36 or the secondary local wireless interface 46, as describedbelow. It should be noted that traditionally each of the layers of theprotocol stack had interfaces to only adjacent layers in the protocolstack. For example, the data link layer 42 would only have interfaces tothe network layer 40 and the physical layer 44. However, according tothe present invention, the cross-layer agent 56 and the network agents58 and 60 establish interfaces enabling interaction between non-adjacentlayers in the protocol stack. Thus, for example, in a point-to-pointtransfer the network layer 40 and the link layer 42 may not be neededand may therefore be by-passed to provide a more efficient transfer.

The network agents 58 and 60 may be implemented in hardware, software,or a combination of hardware and software and operate to monitor theprimary and secondary local wireless interfaces 36 and 46 and report theperformance of the local wireless interfaces 36 and 46 to thecross-layer agent 56. For example, the network agents 58 and 60 maymonitor and report information such as, but not limited to, LAN IPaddresses of other user devices having secondary local wirelessinterfaces for direct P2P communication with RF frequencies available,the current usage of these secondary local wireless interfaces,available bandwidth of each of these secondary local wirelessinterfaces, and Quality of Service (QoS) for each of these secondarylocal wireless interfaces and RF frequencies, and the like. The QoS maybe determined based on Forward Error Correction (FEC), acknowledgedversus non-acknowledged packets, RF power margins, and the like.

The cross-layer agent 56 may be implemented in software, hardware, or acombination of hardware and software. The cross-layer agent 56 mayoptionally be implemented as part of either the P2P application 28 orthe file transfer application of the P2P application layer 30 or thefile transfer application layer 32, respectively. The cross-layer agent56 may receive information from the network agents 58 and 60 and may beinvoked by either the P2P application layer 30 or the file transferapplication layer 32 to control the protocol stack switch 34 such that afile transfer is effected through either the primary or secondary localwireless interface 36, 46, as described below.

FIG. 3 is a flow chart illustrating the operation of the cross-layeragent 56 according to an exemplary embodiment of the present invention.Note that this discussion is equally applicable to cross-layer agents onthe user devices 20 and 22. First, a file transfer is initiated byeither the P2P application layer 30 or the file transfer applicationlayer 32 (step 100). The desired recipient of the file transfer is theuser device 22. The cross-layer agent 56 then determines whether one ormore alternate transfer criteria are met (step 102). More specifically,the cross-layer agent 56 may determine whether the user device 22 isequipped with a secondary local wireless interface and is within a localwireless coverage area of a secondary local wireless interface of theuser device 18. The alternate transfer criteria may include a file sizeof the file to be transferred, a history of the primary and secondarynetwork availability, a priority level of the transfer, a file type ofthe file to be transferred, and the like. This would include determiningif the additional time and overhead associated with configuring thesecondary transfer out-weighs the benefits of by-passing the accesspoint 12. The cross-layer agent 56 may determine whether the alternatetransfer criteria are satisfied based on, at least in part, informationregarding the primary and secondary local wireless interfaces 36 and 46provided to the cross-layer agent 56 from the network agents 58 and 60.

For the file size, the cross-layer agent 56 may determine whether thefile size of the file to be transferred is greater than a threshold filesize. If so, the file may be preferably transferred by a direct P2Pcommunication link. Regarding network availability, the cross-layeragent 56 may determine whether the primary or secondary network has beenfrequently unavailable or available in the past and determine whether totransfer the file by a direct P2P communication link based on, at leastin part, the history of network availability. As for priority, fileshaving a high priority may preferably be transferred via, for example, adirect P2P communication link. Regarding file types, files ofpredetermined file types, such as multimedia file types, may preferablybe transferred via direct P2P communication.

If the alternate transfer criteria are not met, the cross-layer agent 56controls the protocol stack switch 34 to couple the file transferapplication layer 32 to the transport layer 38 of the primary localwireless interface 36, thereby effecting transfer of the file to theuser device via the access point 12 (step 104). When transferring thefile via the access point 12, packets corresponding to the file aretransferred to the access point 12 via the primary wirelesscommunication link between the user device 18 and the access point 12,and the access point 12 then routes the packets to the user device 22via the primary wireless communication link between the access point 12and the user device 22. Once the transfer is complete, the cross-layeragent 56 notifies the initiating application, which is either the P2Papplication 28 of the P2P application layer 30 or the file transferapplication of the file transfer application layer 32 (step 106).

Returning to step 102, if the alternate transfer criteria are satisfied,the cross-layer agent 56 then determines whether bandwidth is availablefor a direct P2P transfer based on the information from the networkagent 60 associated with the secondary local wireless interface 46 (step108). If bandwidth is not available, a wait counter is incremented (step110), and the cross-layer agent 56 determines whether it should continueto wait for available bandwidth (step 112). The cross-layer agent 56 maydetermine whether to wait based on the wait counter. For example, thecross-layer agent 56 may continue to wait until the wait counter reachesa predetermined threshold. The predetermined threshold may be fixed forall transfers or may be a function of factors such as a priority of thefile transfer, network conditions, or the like. If the bandwidth doesnot become available during the permitted wait period, the cross-layeragent 56 controls the protocol stack switch 34 to couple the filetransfer application layer 32 to the transport layer 38 of the primarylocal wireless interface 36 to effect transfer of the file via theaccess point 12 (step 104).

Returning to step 108, if bandwidth is available, the cross-layer agent56 controls the protocol stack switch 34 to couple the file transferapplication layer 32 to the transport layer 48 of the secondary localwireless interface 46, and a direct P2P wireless communication linkbetween the user devices 18 and 22 is established (step 114). The fileis then transferred to the user device 22 via the direct P2P wirelesscommunication link, thereby bypassing the access point 12 and minimizingthe use of RF spectrum (step 116). Once the file has been transferred,the direct P2P wireless communication link between the user devices 18and 22 is torn down, or terminated (step 118), and the initiatingapplication is notified that transfer is complete (step 106).

FIG. 4 is a block diagram of an exemplary embodiment of the user device18 of FIG. 1. Note that this discussion is equally applicable to theuser devices 20 and 22. In general, the user device 18 includes acontrol system 62 having associated memory 64. The memory 64 storessoftware instructing the user device 18 to operate according to thepresent invention. More specifically, in one embodiment, the P2Papplication 24, the file transfer application of the file transferapplication layer 32, the protocol stack switch 34, the cross-layeragent 56, and the network agents 58 and 60 may be implemented, at leastin part, in software and stored in memory 64. The user device 18 mayalso include a storage unit 66 for storing files, such as, but notlimited to, multimedia files that may be transferred to the user devices20, 22 according to the present invention. The storage unit 66 may beany digital storage unit. As an example, the storage unit 66 may be oneor more hard disc drives or the like. Alternatively, files may be storedin memory 64. The user device 18 also includes the primary and secondarylocal wireless interfaces 36 and 46. In addition, the user device 18includes a user interface 68, which may include components such as, butnot limited to, a display, an input device, speakers, and the like.

Those skilled in the art will recognize improvements and modificationsto the preferred embodiments of the present invention. All suchimprovements and modifications are considered within the scope of theconcepts disclosed herein and the claims that follow.

1. A method for transferring a file from a first user device within awireless local area network to a second user device within the wirelesslocal area network comprising: providing a primary local wirelessinterface for the first user device, the primary local wirelessinterface having a physical layer, a data link layer, a network layer,and a transport layer; providing a secondary local wireless interfacefor the first user device, the secondary local wireless interface havinga physical layer, a data link layer, a network layer, and a transportlayer; providing a control system associated with the primary andsecondary local wireless interfaces, the control system comprising: afirst network agent operatively associated with the primary localwireless interface, the first network agent monitoring at least one ofthe physical layer, the data link layer, the network layer, and thetransport layer of the primary local wireless interface; a secondnetwork agent operatively associated with the secondary local wirelessinterface, the second network agent monitoring at least one of thephysical layer, the data link layer, the network layer, and thetransport layer of the secondary local wireless interface; and across-layer agent obtaining information regarding the secondary localwireless interface from the second network agent, and determining totransfer the file to the second user device via a direct point-to-pointwireless communication link based on at least a portion of theinformation regarding the secondary local wireless interface; andinitiating a file transfer of the file from the first user device to thesecond user device; determining to transfer the file to the second userdevice via the direct point-to-point wireless communication link wherethe secondary local wireless interface communicates with the second userdevice using the direct point-to-point wireless communication link; ifthe file is to be transferred via the direct point-to-point wirelesscommunication link: establishing the direct point-to-point wirelesscommunication link with the second user device; and transferring thefile to the second user device via the direct point-to-point wirelesscommunication link, thereby bypassing an access point.
 2. The method ofclaim 1 wherein the primary local wireless interface communicates withthe access point and wherein establishing the direct point-to-pointwireless communication link comprises establishing the directpoint-to-point wireless communication link with the second user deviceusing the secondary local wireless interface.
 3. The method of claim 2further comprising: determining whether to transfer the file via thedirect point-to-point wireless communication link or via the accesspoint; and transferring the file to the access point via a first localwireless communication link between the first user device and the accesspoint if the file is to be transferred to the second user device via theaccess point, wherein the access point routes the file to the seconduser device via a second local wireless communication link between theaccess point and the second user device.
 4. The method of claim 3 themethod further comprising establishing the first local wirelesscommunication link between the first user device and the access pointusing the primary local wireless interface.
 5. The method of claim 3wherein determining whether to transfer the file to the second userdevice via the direct point-to-point wireless communication link or viathe access point comprises determining whether the second user device iswithin a local wireless coverage area of the secondary local wirelessinterface.
 6. The method of claim 5 wherein determining whether totransfer the file to the second user device via the directpoint-to-point wireless communication link or via the access pointfurther comprises determining whether a file size of the file is greaterthan a predetermined threshold.
 7. The method of claim 5 whereindetermining whether to transfer the file to the second user device viathe direct point-to-point wireless communication link or via the accesspoint further comprises determining whether a file type of the file isone of a predetermined list of file types.
 8. The method of claim 5wherein determining whether to transfer the file to the second userdevice via the direct point-to-point wireless communication link or viathe access point further comprises determining whether to transfer thefile to the second user device via the direct point-to-point wirelesscommunication link based on a priority of the file.
 9. The method ofclaim 5 wherein determining whether to transfer the file to the seconduser device via the direct point-to-point wireless communication link orvia the access point further comprises determining whether to transferthe file to the second user device via the direct point-to-pointwireless communication link based on a history of performance for theprimary and secondary local wireless interfaces.
 10. The method of claim1 wherein determining whether to transfer the file to the second userdevice via the direct point-to-point wireless communication link or viathe access point further comprises determining whether bandwidth isavailable for the direct point-to-point wireless communication link. 11.A user system comprising: a) a first local wireless interface adapted toestablish a first wireless communication link with an access point of awireless local area network, the first local wireless interfaceincluding a physical layer, a data link layer, a network layer, and atransport layer; b) a second local wireless interface, the second localwireless interface including a physical layer, a data link layer, anetwork layer, and a transport layer; and c) a control system associatedwith the first and second local wireless interfaces, the control systemcomprising: a first network agent operatively associated with the firstlocal wireless interface, the first network agent monitoring at leastone of the physical layer, the data link layer, the network layer, andthe transport layer of the first local wireless interface; a secondnetwork agent operatively associated with the second local wirelessinterface, the second network agent monitoring at least one of thephysical layer, the data link layer, the network layer, and thetransport layer of the second local wireless interface; and across-layer agent obtaining information regarding the second localwireless interface from the second network agent, and determining totransfer the file to a second user system via a direct point-to-pointwireless communication link based on at least a portion of theinformation regarding the second local wireless interfaces, wherein thecontrol system: i) initiates a file transfer of a file to the seconduser system; ii) determines to transfer the file to the second usersystem via the direct point-to-point wireless communication link; andiii) if the file is to be transferred via the direct point-to-pointwireless communication link: A) establishes the direct point-to-pointwireless communication link with the second user system using the secondlocal wireless interface; and B) transfers the file to the second usersystem via the direct point-to-point wireless communication link,thereby bypassing the access point.
 12. The user system of claim 11wherein the control system determines whether to transfer the file tothe second user system via the direct point-to-point wirelesscommunication link or via the access point associated with the wirelessaccess local area network and if the file is to be transferred to thesecond user system via the access point, the control system furthertransfers the file to the access point via the first wirelesscommunication link between the user system and the access point, whereinthe access point routes the file to the second user system via a secondwireless communication link between the access point and the second usersystem.
 13. The user system of claim 12 wherein in order to determinewhether to transfer the file to the second user system via the directpoint-to-point wireless communication link or via the access point, thecontrol system further determines whether the second user system iswithin a local wireless coverage area of the second local wirelessinterface.
 14. The user system of claim 13 wherein the control systemfurther determines whether to transfer the file to the second usersystem via the direct point-to-point wireless communication link or viathe access point based at least in part on a file size of the file. 15.The user system of claim 13 wherein the control system furtherdetermines whether to transfer the file to the second user system viathe direct point-to-point wireless communication link or via the accesspoint based at least in part on a file type of the file.
 16. The usersystem of claim 13 wherein the control system further determines whetherto transfer the file to the second user system via the directpoint-to-point wireless communication link or via the access point basedat least in part on a priority of the file.
 17. The user system of claim13 wherein the control system further determines whether to transfer thefile to the second user system via the direct point-to-point wirelesscommunication link or via the access point based on at least a historyof performance for the first and second local wireless interfaces. 18.The user system of claim 12 wherein in order to determine whether totransfer the file to the second user system via the directpoint-to-point wireless communication link or via the access point, thecontrol system further determines whether bandwidth is available for thedirect point-to-point wireless communication link.
 19. The user systemof claim 1 wherein the first and second local wireless interfacesoperate in essentially non-overlapping frequency bands.
 20. The usersystem of claim 12 wherein the control system further comprises: anapplication that initiates the file transfer; and a protocol stackswitch controlled by the cross-layer agent to couple the application tothe first local wireless interface when the cross-layer agent determinesthat the file is to be transferred via the access point and to couplethe application to the second local wireless interface when thecross-layer agent determines that the file is to be transferred via thedirect point-to-point wireless communication link.
 21. The user systemof claim 11 wherein the user system and the second user system arepersonal video recorders.